In fact, it's happened often enough that Prime Minister Matteo Renzi of Italy is now calling for the European Union to hold an emergency summit to address the crisis. According to the The Washington Post, some 400 people drowned after a boat capsized in the waters off the coast of Malta just last week, bringing the number of people killed in similar accidents in the Mediterranean to more than 1,500. Renzi said human traffickers who cram "rickety ships" full of immigrants desperate to escape war and poverty are to blame for the sharp increase in the death toll, reported The New York Times.

It appears that on Sunday, passengers on the doomed boat were trying to catch the attention of a passing Portuguese merchant ship, with many rushing to one side of the boat at the same time, the BBC reported, with many falling overboard. According to Maltese prime minister Joseph Muscat, the ship involved in Sunday's accident was relatively large, with several tiers, all filled with passengers, The New York Times reported. "Most of the people who died are still trapped in the ship," Muscat told the Times.

European Union officials pledged Sunday to improve the response to such incidents, but specifics were widely varied. Some called for more rescue personnel to be dedicated to its Triton rescue effort, which took over for the Italian-operated Mare Nostrum rescue detail last year; others called for crackdown on Libya, a country which, Muscat told the Times, allows human traffickers to operate in relative freedom.

But the aid agency Save the Children, which works closely with immigrants in Italy, had harsh criticism for the EU's inability to decide what action to take to address the growing crisis and the resulting repeated accidents on the Mediterranean. In a statement to The Guardian, the group called for Mare Nostrum to be revived: "It is time to put humanity before politics and immediately restart the rescue. Europe cannot look the other way while thousands die on our shores."